The statement that “children today may be on track to have a shorter lifespan than their parents” comes from a report published in the New England Journal of Medicine. The article can be found under:

Olhansky, J., Passaro, D., Hershow, R., Layden, J. et al. (2005, May 17). A Potential Decline in Life Expectancy in the United States in the 21st Century. The New England Journal of Medicine, 352 (11), 1139-1144.